Heater Fan, Never cleaned out since 1969! Options

[914sgofast2]

As one of the "while I'm in here, might as well do this too" type of jobs to be done when I was replacing the gas tank, I removed my heater fan box to investigate why the heater/defroster fan never worked since we bought this car in 2016. It's a model year 1970 that was built in December 1969 according to the door jamb sticker.

The heater fan box was completely filled up with leaves and debris. These early cars did not have a screen used under the air intake louvers. The fan motor couldn't turn at all with all the leaves, twigs, and dirt built up in the heater plenum and vent outlets. No wonder the motor had burned out. Here is a photo for your viewing enjoyment showing what I discovered upon separating the fan from the heater box housing:

[vitamin914]

Pulling out the gas tank is not a simple procedure for inspection. Anyone know from what model year onward screens were put on to prevent this?

... These early cars did not have a screen used under the air intake louvers. The fan motor couldn't turn at all with all the leaves, twigs, and dirt built up in the heater plenum and vent outlets. No wonder the motor had burned out. Here is a photo for your viewing enjoyment showing what I discovered upon separating the fan from the heater box housing:

[maf914]

Anyone know from what model year onward screens were put on to prevent this?

According to the 914 Restorer's Guide the cowl intake screen was added in June 1973.

I wonder how much debris is in the fan on my 76 which does have an intake screen?

I had a 92 Nissan pickup and small oak leaves would get into the ventilation fan and sometimes get stuck in a position that would allow them to paddle the centrifugal fan blades. Sort of like cardboard paddles on bicycle wheel spokes. Annoying. Luckily the fan could be accessed from under the dash fairly easily.